Martin Freeman has confessed he had his doubts about filming the wedding episode of Sherlock with his real-life partner Amanda Abbington.

The couple have been together for 13 years and have two young children, but have never tied the knot. Amanda joined the cast of Sherlock for the third series as John Watson's new love interest Mary Morstan and they married in the second episode The Sign Of Three.

Speaking during an appearance at the Regent Street branch of the Apple Store, Martin admitted he had reservations the episode would come across as too sentimental, the Metro reported.

"I definitely had reservations when I read it," Martin confessed. " We talked about it, and I said, 'Has this gone a bit too mushy? Sherlock's being very, very adept all of a sudden at being emotional'.

"And [writer] Steven Moffat said, 'No, what we're gonna do, in episode three, is completely rip the rug out from under people's feet, just as they think that they're seeing a slightly different sort of show, we'll give it to them both barrels'."

Benedict Cumberbatch agreed: "It's a very fine line to tread, but I think we got away with it, and then you crash in with the mystery. I thought it was a wonderfully complex bit of storytelling."

But some fans criticised the new series of the BBC drama, taking to Twitter to complain it had become an "unfunny sitcom".